This invention relates to water sports devices generally and in particular, to water sports devices incorporating multiple planing surfaces.
For years, efforts have been made to develop a water sports device which would rival the popularity of traditional water skis. Water skiing is popular because although the sport is relatively easy to learn, high speed maneuvering and jumping are challenging and exciting even for the experienced skier. Traditional water skis are, of course, not without their drawbacks. Specifically, skiing for more than a short duration can require a great deal of leg and lower back strength. Furthermore, skiing puts a great deal of stress on the rider's legs, particularly the knees, all too often resulting in injury.
Numerous attempts have been made to develop a desirable alternative to traditional water skiing by incorporating hydrofoils on skis, knee boards and water sleds. A hydrofoil is a blade attached to the bottom of a craft at a small angle to the horizontal so that when the craft is in motion, the fluid striking each blade's underside creates a high pressure region below the blade, low pressure above it, resulting in lift that raises the craft out of the water, thereby reducing drag at high speeds. Unfortunately, each of these efforts has suffered from a number of serious drawbacks.
For example, U.S. Pat No. 2,751,612 teaches the attachment of a hydrofoil device to each ski of the user. A pair of channel members are adapted to be adjustably secured along the sides of the water ski by a pair of nuts and bolts from which depend downwardly extending, inwardly inclined front and rear struts secured to an oval-shaped member between which is supported a hydrofoil unit. Unfortunately, experience has shown this device to be virtually impossible to ride in that the hydrofoil unit provides too narrow base for the rider to balance upon.
Another hydrofoil and ski arrangement is disclosed by U.S. Pat. No. 3,164,119. This reference teaches a single V-shaped hydrofoil lift having upwardly diverging legs, the upper ends of which are provided with inwardly extending horizontal limbs to which skis may be attached. The lower convergent ends of the legs are secured by means of welding or bolts to a horizontally disposed boom having an axis extending forwardly and rearwardly of the planar legs and perpendicular thereto. Foils are attached to the boom forwardly and rearwardly of the strut and transversely of the boom, the forward foil being attached to the upper side of the boom and allegedly having a positive lifting effect and the rearward foil being attached to the underside of the boom and allegedly having a negative lifting effect.
Unfortunately, riding this hydrofoil ski arrangement is extremely difficult. The hydrofoil arrangement requires high speed and the lift of the V-shaped converging legs of the strut to lift the rider from the water. Unfortunately, even when the tow boat is moving at a constant speed, if the rider attempts to maneuver the skis, the effective speed of the hydrofoil skis through the water changes, thereby raising or lifting the skis. The change in lift resulting from the change in the proportion of the V-shaped strut in the water is difficult for the rider to adjust to. In addition, as the lenticular shape of the strut is drawn through the water, the resistance of the water causes vortices, making it extremely difficult for most skiers to maintain control of the skis. Furthermore, the extremely thin lifting and stabilizing bars cause extreme front and rear instability, resulting in rapid rises and descents. Specifically, it is extremely difficult and tiring for the rider to maintain his or her ankles in a 90.degree. locked position to maintain the hydrofoil at a constant height.
This is likewise true of the kneeboard arrangement disclosed by the same reference. The kneeboard incorporates two depending vertical struts from which is secured a boom extending roughly the length of the kneeboard. As in the case of the ski arrangement, foils are attached forwardly and rearwardly of the struts, the forward foil being attached to the upper side of the boom and having a positive lifting effect and the rearward boom being attached to the underside of the boom and having a negative lifting effect. In addition to the aforementioned vertical instability. As is true of kneeboards in general, the board is difficult to maneuver. Likewise, as with kneeboards in general, kneeling soon proves to be an uncomfortable position, particularly if the board jumps from the water.
Another approach is taught by U.S. Pat. No. 3,105,249, which teaches a hydrofoil apparatus built somewhat like a bicycle or steerable sled. The reference teaches the use of a front and rear hydrofoil structure, each of which is secured to a vertical member. Each vertical member in turn is connected to the other by a horizontal bar. The rear hydrofoil assembly is fixedly secured to the horizontal member and a seat is mounted on the horizontal member proximate the junction between the horizontal member and the vertical member. The front vertical member is mounted in such a manner as to be pivotable relative to the horizontal member, and a pair of handle bars is secured to the vertical member to enable the rider to control this pivot action. The front hydrofoil structure is generally triangular with an upper horizontal member and two converging lower members. The rear hydrofoil structure comprises a trapezoidal structure resembling a truncated triangle, having parallel upper and lower horizontal members and two converging connecting members. The apparatus is towed by means of a tow rope secured to the bottom of the front hydrofoil structure. The reference teaches that as the apparatus moves through the water, the reaction between the hydrofoils and the water causes the apparatus to rise until only the lower portion of the converging foils are below the surface of the water.
As with the other hydrofoil apparatuses, this device is unstable, particularly at high speeds, due to the tendency of the hydrofoils to shoot out of the water. Likewise, as with other triangular hydrofoil structures, the converging lenticular shape of the vertical legs cause extreme vortices when turning, making it difficult to control the device. Finally, as is apparent from the configuration of the device, riding the apparatus is very dangerous, in that, in the event of a fall, the rider is likely to be thrown against the horizontal connecting bar or the handle bars of the device.
Accordingly, there is needed an improved water sports device which requires only a moderate level of skill to ride while offering the excitement of maneuvering and jumping for the more advanced rider. Desirably, the water sports device should provide these attributes without requiring the physical endurance demanded by traditional water skis and without exerting high levels of stress on the legs of the rider.